Hi,
We are designing a module with nRF54LM20 + nRF7002 (WLCSP) and want to share the 2.4 GHz antenna between Wi-Fi and BLE, following your coexistence guidance (shared antenna mode, PTA, external SPDT controlled by SW_CTRL0, 2.4/5 GHz diplexer to a dual-band antenna).
The BLE path uses an external FEM (Skyworks SKY66114-11) with up to +22 dBm output. The SPDT (Infineon BGS12WN6) has 37 dB typical / 31 dB minimum isolation at 2.4 GHz. When the FEM transmits, the nRF7002 2.4 GHz RF port will therefore see roughly −15 dBm typical and up to about −9 dBm worst case.
The nRF7002 Product Specification v1.2 (Table 12, Absolute maximum ratings) lists “RF input level: −10 dBm”.
Our questions:
- Does the −10 dBm absolute maximum apply in all nRF7002 states: powered off (VBAT off), sleep/shutdown, idle, and active RX/TX? Or is the 2.4 GHz port more robust when the device is not actively receiving?
- Is the limit specified for CW, and is there a higher allowable level for short, duty-cycled bursts (BLE packets of a few hundred µs)?
- When nRF7002 is not active or has granted the antenna to the short-range radio, what does its 2.4 GHz port look like (impedance, internal T/R switch state, any internal protection)?
- Do you have a recommended architecture or reference design for a shared antenna where the short-range radio uses an external FEM at +20 to +22 dBm? What total isolation toward the nRF7002 RF port do you recommend?
- If extra protection is needed, what do you recommend: a shunt switch to ground at the nRF7002 2.4 GHz port, two switches in series, a limiter, or an attenuator? What added insertion loss is acceptable for Wi-Fi?
- We also have an LR1120 transmitting up to +12 dBm at 2.4 GHz on a separate antenna. What antenna-to-antenna isolation do you recommend toward the nRF7002 when it is idle or off?
- Do the limits differ between the QFN and WLCSP variants?